This color display uses SPI to receive image data. That means you need at least 4 pins - clock, data in, tft cs and d/c. If you'd like to have SD card usage too, add another 2 pins - data out and card cs. However, there's a couple other pins you may want to use, lets go thru them all!
- Lite - this is the PWM input for the backlight control. Connect to 3-5VDC to turn on the backlight. Connect to ground to turn it off. Or, you can PWM at any frequency.
- MISO - this is the SPI Microcontroller In Serial Out pin, its used for the SD card. It isn't used for the TFT display which is write-only
- SCLK - this is the SPI clock input pin
- MOSI - this is the SPI Microcontroller Out Serial In pin, it is used to send data from the microcontroller to the SD card and/or TFT
- TFT_CS - this is the TFT SPI chip select pin
- Card CS - this is the SD card chip select, used if you want to read from the SD card.
- D/C - this is the TFT SPI data or command selector pin
- RST - this is the TFT reset pin. Connect to ground to reset the TFT! Its best to have this pin controlled by the library so the display is reset cleanly, but you can also connect it to the Arduino Reset pin, which works for most cases.
- Vcc - this is the power pin, connect to 3-5VDC - it has reverse polarity protection but try to wire it right!
- GND - this is the power and signal ground pin
For the level shifter we use the CD74HC4050 which has a typical propagation delay of ~10ns